It’s 3pm, but Royal Blood are tired. They have every right to be. The last few months have seen the duo criss-cross the Atlantic and the English Channel, even squeezing in a two-gig trip to Australia. Showcases, festivals, support slots; 76 shows and counting, and it’s not even the middle of July. As summer progresses, their gruelling schedule is due to kick up another notch; there are more US dates, appearances at pretty much every major European festival, before yet another trip round America and Canada in the autumn, supporting Pixies. And, in the middle of all that, the small matter of releasing their debut album, one of the year’s most anticipated records. Meteoric doesn’t quite do their rise justice.

They’re here in Manchester as part of Summer in the City, our afternoon appointment the result of an early stage time; they’re on at 6.30pm, before Maxïmo Park and Pixies, and before a overnight drive to tomorrow’s show, an afternoon slot at T in the Park. Their dressing room for today, a room in the hotel next to the venue, is hot and cramped – several people from their label, management, and crew are tapping away at phones and laptops – but there’s a sleepy, relaxed vibe; the TV is tuned to live golf, and plates of fruit are passed around. Sprawled next to each other on the bed, drummer Ben Thatcher looks positively comatose, leaving his bandmate, singer and bassist Mike Kerr, to do most of the talking.

Thoughtful and softly-spoken, Kerr is quietly engaging. He listens intently, occasionally tugging at his mop of curly hair or gently correcting misinformation from past interviews, and gives intelligent, considered answers – not many rock musicians accurately quote Shakespeare. Once Thatcher warms up a little, they slip into the matey habit of finishing each other’s sentences, evidence of a deep bond and years spent in each other’s company; eight, to be precise. It’s far removed from the confident swagger of a band who specialise in pummelling blues rock and have Jay-Z’s “99 Problems” as walk on music, and there’s genuine appreciation and more than a little surprise as they consider just how far they’ve come in such a short space of time.

In a year of highs – inclusion on the BBC Sound of 2014 longlist, appearing on ‘Jimmy Kimmel Live’, Jimmy Page declaring himself a fan, playing alongside Arctic Monkeys at their Finsbury Park shows – tonight still ranks as one of the biggest. After consulting his iPhone, Thatcher declares that they were doing “absolutely nothing” 12 months ago and that, back then, never in their wildest dreams could they have imagined sharing a stage with Frank Black & co, handpicked as support.

“It’s pretty mad,” agrees Kerr. “We felt lucky that we’d found such a good manager and had had a bit of support from the Monkeys, but that doesn’t really equal anything, you know? We hadn’t even put a song out yet so we had no gauge of whether what we were doing had any shelf life at all. We were just writing and preparing ourselves for gigs, and going out there and giving it a go.” To hear them tell it, the trip from empty pubs to one of the UK’s most exciting, in-demand bands has been a hell of a ride. And they’re just getting started.

Kerr and Thatcher have been in various bands on and off since their mid-teens, but their interest in music goes back much further; both have played since childhood. Thatcher got his first drum kit aged six, while Kerr, far from dreaming about guitar solos or walls of distortion, played piano. “I got to Grade Three,” he tells me, “but I can’t read music so I stopped going to lessons when I was 11. I started learning on my own, and decided I wanted to learn all of Bohemian Rhapsody. Then I learnt some Scott Joplin.” He can, he claims, still play the seminal Queen hit, and his dislike of formal music training’s rigid structures – “I didn’t like the grades, they held me back” – is evident in his inventive, unorthodox approach to his current instrument.

As with many teenage interests, what started as a hobby became something of an obsession. “I found myself playing all the time, even at school; I wouldn’t go out and do anything, I’d just go to the music room and play piano all day. I wanted to do it as much as I could.” Such dedication led to endless trips to college music nights along the south coast and, in a tight knit scene, it wasn’t long before the two met, introduced by mutual friends in Chichester. Soon after that, they were playing in the same bands.

Those were, it seems, heady days. Kerr thought Thatcher was “mental, off the wall crazy. He was the kid you thought had had too much lemonade,” and recalls him turning up for a show in a tuxedo. For his part, Thatcher remembers “thinking that what Mike was doing was really interesting to watch; he was a performer.” Full of bravado or just game for a laugh, this theatrical streak led to him being sprayed with gold car paint – “When it dried I couldn’t move my skin, and I started freaking out I was going to die, Goldfinger style” – and donning a fur jacket one night, an approach that paid dividends. “We met our manager [that night] didn’t we?” chuckles Kerr. “Maybe we should do it again.”

Having bounced around various different groups, the catalyst for setting up as a duo was as much what they didn’t want to achieve as what they did; chasing success had left Kerr in particular somewhat disillusioned, and that wasn't a priority for the new project. “In my first band, that was all we wanted. But when we started, we’d exhausted that idea and decided to have no agenda other than just enjoying ourselves.” Their first gig arrived after only an hour’s practice, but they pulled it off; since then, they’ve made a point of placing fun at the heart of what they do, a challenge in itself considering the amount of hype and expectation that’s accompanied them since first single ‘Out of the Black’ appeared early last November.

Hardly a year goes by without a slew of articles proclaiming “the death of guitar music” – although what’s really being suggested is the death of a particular brand of traditional, white, working class rock – closely followed by a handful of bands anointed as its “saviours”; like countless others before them, Royal Blood are the current chosen ones. Drenge, one of the class of 2013, were particularly upset with being hailed as “the Derbyshire Black Keys”, but Kerr’s sanguine about lazy pigeon holing. “Being a new band, you spend half your time just defending yourself against comparisons, and it seems you get to a point where you’re at the other end of that. I just feel sorry for the next band that’s going to get the question about Royal Blood and go: ‘Obviously, we sound a little bit like them but, you know…’ and it’s just going to go on and on and on. When Led Zeppelin started, all they got was: ‘You sound like Black Sabbath!’ You look back at that now and it’s a fucking joke. How did that even happen?”

The checklist of their supposed influences is obvious. The White Stripes, The Black Keys, Deap Valley; duos one and all, the two-word names provide a neat symmetry amid the yin yang, crash’n’bang combo of drums and guitar. “Royal Blood” sounds calculated, and despite Kerr protesting that it’s “pretty random. The words just fell out of my mouth,” they did give it some thought. “Trying to come up with a name was just a nightmare; what do you call your band, you know? It’s actually quite cool as it has two meanings – one of which is really sinister – and I really liked the idea of having two words, two people and the same number of letters in each word; there’s lots of symmetry in the band and within our work.”

The music of many of these duos falls into two, distinct styles. Some, like the Stripes or Death From Above 1979 have a darker, more experimental edge, happy to indulge their eccentric tastes – witness Jack White, post Get Behind Me Satan, employing Mariachi fanfares and bagpipes. Deap Valley, Japandroids, and the pre-2006 Keys however, borrow from more traditional Delta blues and rock templates, leaving a little less room for personality to shine through. Royal Blood chart a course between these two poles; it’s raw and loud, but they double down on the joyous abandon of infusing the blues with a hook heavy, pop sensibility.

There’s also, to my ears, more than a hint of 80’s hair metal. Aside from the stadium-sized rolling riffs, it’s the tone Kerr achieves and the sprinkling of fuzzed out, hammer-on-hammer-off descending guitar lines – the breakdown of new single ‘Figure It Out’ being a prime example. He disagrees. “If you want to get technical about it, some of the songs consist of literally just the blues chords, and the same changes as old blues standards. I only have four strings, and I rely on open notes quite a lot, but for many [of the songs], if you break them down to the piano, it’s the same chords and patterns.”

These structures are worked out in long, call and response jam sessions, where Kerr and Thatcher throw ideas at each other and see what sticks. Confessing that “We’ve never gone into a room, sat down saying: ‘Let’s write a really good song,’ and come out with one,” Kerr says the creative process is “quite mysterious. I don’t think anyone really knows how you write a song, but our main principle is just to get together and start having fun. It almost feels like every idea that’s turned into a song has been something we’ve stumbled across by accident. ‘Out of the Black’ is a good example; the rhythm was something Ben was tapping out in a pub one night, as we were having a pint, and later, after filming a rehearsal and watching the playback, we noticed him sitting in the background playing it quietly. We thought it was wicked, and it turned into a song.”

Musically, it’s a completely equal collaboration – “that’s our only strength as a two piece,” says Kerr. “It’s all about our chemistry” – but the lyrics are his domain, with Thatcher handling production duties. Studio disagreements can be particularly hard for duos, but something they’ve yet to experience. “It’s never, ever got to the point where one has tried to put their foot down the other’s throat. Plus, our favourite ideas are always the ones we’ve both immediately enjoyed and gone: ‘Fuck, that’s great! Do that again!’”

“We really are on the same wavelength,” concurs Thatcher, “but we’d never shut down a good idea either. We both have a standard of what we think is great and fortunately, they match right now.”

The most striking thing that hits you about Royal Blood is, style aside, the sounds and the sheer noise they create; a full on sonic assault that punches you in the gut and makes your hairs stand on end. There’s none of the blistering mess that so many garage rock bands fall back on, but it’s not streamlined and clean either. Distortion is front and centre, but there’s a warmth to it, and as the songs barrel along they quickly envelop the senses and invade your limbs – dancing is pretty much unavoidable. That all this comes from just Kerr’s fingers and four strings is due to three things: a sense of adventure, an extremely long period of experimentation, and one very lucky mistake.

“I got really into distortion first – there’s a band called Haunts that had this great distortion sound, and I started listening to early Muse albums, which had the big bass sounds – then I started splitting my signal a lot and just adding amplifiers. It became a bit of a… not an obsession, but just fun. When we started I had what I do now on a more basic level but, after ‘Come On Over’, I was convinced we would get away with doing it this way. Every day I’m figuring out new ways of expanding it, and it’s still developing. We were chasing the idea of being in a band with a small number that sounds like there are more; there’s only two of us and we are trying to sound like there are four.”

Kerr’s Eureka moment arrived, as they are wont, courtesy of serendipity. “I saw this guy using an octave pedal, he was playing too high on the bass – like really high – and adding octaves below. That’s something guitarists do a lot and I started wiring my bass up with higher strings and adding octaves below and, without giving too much away, I bought the wrong pedal. I wired it up the opposite of how I wanted to do it and I was like: ‘Fuck, that’s it! That’s a great sound!’ I phoned up my friend George, and he came round my house and agreed. And that was that.”

He’s been coy in previous interviews about discussing his exact set up, and he refuses to say anything about the magic ingredient in his pedal board beyond “one of them is my own pedal, a tuner actually. I didn’t make it, but a friend did; you can’t buy it. It’s probably the greatest tuner ever.” But he doesn’t just rely on electronic wizardry; there are a few old school tricks he employs to great effect. “For one track I used guitar strings because I wanted to use a bottleneck slide on the bass, but you can’t really do that with bass strings; they don’t resonate the same way. I use short scale basses anyway, and you can just about fit a guitar string on there. It was more of a ‘why not’ type of thing really.”

The song in question – “some serious shit, I pulled it off really well” – sadly didn’t make it on to their self-titled debut album, but the ten that did are a near flawless collection of dynamic, intriguing tracks that, unlike a lot of rock albums, reward repeatedly listening; after six weeks in its company, it’s as enjoyable and infectious as ever. Warner left them and long-time studio cohort Tom Dalgety to their own devices – “there’s this myth around labels which says as soon as you sign a deal, say goodbye to your own decisions and creativity but really, they have done nothing but nurture that with us” says Kerr – safe in the knowledge that if the band were happy, they’d be too.

Deciding against re-recording the three songs that had already appeared as singles, the process seems to have been fairly straightforward – “we’re a well-oiled [studio] machine” according to Kerr – and they swear there are no overdubs, no trickery, and precious little tracking; if it can’t be done live and reproduced on stage, they’re not interested. “I love the idea of people thinking there are guitars on it, coming to a show and realising it’s just us; that’s the aim. Even to the point where we were doing one of our songs the other day, and there was one particular note I wanted to include but couldn’t, because it was impossible to play. We changed the note by tuning the string down because if I can’t do it on stage, I’m not doing it at all.”

Part of the reason their music stands up to in-depth listening is Kerr’s lyrics. Humorous, poetic, and clever – one track is inspired by a line from Shakespeare’s As You Like It – they avoid the typical “beer’n’broads” or “woe-is-me” self-pity that’s been such a rich source material for many of rock’s practitioners. They’re still deeply personal, but delivered with a caustic wit that raises a dry smile; “You made a fool out of me” he snaps on ‘Out of the Black’, before ominously adding “I’ve got a gun for a mouth / And a bullet with your name on it.” Romance gets a lurid makeover – “I’ve got love on my fingers / Lust on my tongue” goes ‘Little Monster’s central refrain – but it’s loss and betrayal that provide the songs’ main emotional thrust.

“A lot of them were written at two in the morning, trying not to wake anyone up and perhaps not even written in one sitting. I guess the running theme through all of them is my struggle with quite a messy break-up situation, and it being the first one that was quite real. Before that, I hadn’t really written lyrics, but that spurred me on. Some lines come out of nowhere, or start out as a bit of a joke almost, but then you think: ‘Actually, that’s got something in there.’”

Kerr has three main vocal heroes, and ‘Loose Change’ sees him mimic one of them; the tumbling, scattergun delivery and imagery of Jack White. “Teeth clean / Nineteen / Heart’s Queen / Looking on the guillotine” he yelps, and he takes the comparison as a compliment. “Robert Plant, vocally, is a big influence because I hear so much of him in my other two favourite singers, White and Jeff Buckley. It’s quite interesting how different Buckley’s voice is from White’s, yet they both point towards the same person. They’re all so different, but there are so many different ways of singing in Robert Plant’s voice; he seems to accommodate every song differently. But I take more inspiration from Buckley’s delivery and his choices rather than lyrically. He is, as far as I’m concerned, quite untouchable as far as lyrics and writing go, there’s no one that writes like him.”

Later, with the sun beating down on a half-full Castlefield Bowl, Kerr and Thatcher casually stroll on stage and do their thing. It is electric. It’s the second time I’ve seen them, and while there’s no doubt they’re more suited to late night basements filled with half-cut revellers, they make short shrift of winning over the early evening drinkers. The first few tracks are positively received, but it’s once they rip into ‘Figure It Out’ that things really kick up a gear; people push past, eager to get down the front, and a few determined individuals try to get a mosh pit going. Standing in front of his monitors, arm aloft, Kerr wears the look of a man who knows his time now and isn’t about to let it slip from his grasp.

There will be those who deride Royal Blood as derivative or unoriginal, but they should be ushered in the direction of the famous Jean-Luc Goddard quote: “It’s not where you take things from, it’s where you take them to.” Kerr and Thatcher are doing their best to make that destination an interesting place.

“The bass and drum thing isn’t new and neither is using more than one amp. But, even with people that I look up to as guitarists – Jack White say, or Josh Homme – their sounds, and a big portion of what they do, is borrowed, but they put their own stamp on it and that’s what makes a good idea. Even to the point that you don’t know a song but you can tell it’s them, not only because it’s their sound but the way they play. That’s something that I still aspire to be able to do.”

Thatcher, having fully woken up, put’s it more poetically. “With regards to music, and people saying ‘It’s already been done before’, I truly believe that it hasn’t; each song from every single band is completely different. It’s like saying ‘I’ve already seen the sunset!’ Well, every sunset is different, and music’s the same.”